/* Copyright (C) 2025 Aryadev Chavali

 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License Version 2 for
 * details.

 * You may distribute and modify this code under the terms of the GNU General
 * Public License Version 2, which you should have received a copy of along with
 * this program.  If not, please go to <https://www.gnu.org/licenses/>.

 * Created: 2025-04-16
 * Description: Parsing Lisp!
 */

#ifndef READER_H
#define READER_H

#include <lib/vec.h>
#include <lisp/context.h>
#include <lisp/lisp.h>

#define INPUT_CHUNK_SIZE 512
static const char SYM_CHARS[] =
    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
    "¬!£$%^&*_-+={[]}:@~#<,>.?/";

typedef struct
{
  const char *name;
  u64 offset;
  sv_t str;
} input_t;

void input_from_sv(context_t *ctx, input_t *inp, const char *name, sv_t sv);
void input_from_fp(context_t *ctx, input_t *input, const char *name, FILE *fp);
bool input_eof(input_t *input);

typedef struct
{
  u64 col, line;
} pos_t;

pos_t input_offset_to_pos(input_t *inp);

typedef enum
{
  PERR_OK = 0,
  PERR_EOF,
  PERR_UNEXPECTED_CHAR,
  PERR_EXPECTED_CLOSE_BRACKET,
  PERR_EXPECTED_SPEECH_MARK,
  PERR_UNEXPECTED_READER_MACRO_SYMBOL,
  PERR_EXPECTED_BOOLEAN,
} perr_t;

static inline const char *perr_to_cstr(perr_t perr)
{
  switch (perr)
  {
  case PERR_OK:
    return "OK";
    break;
  case PERR_EOF:
    return "EOF";
    break;
  case PERR_UNEXPECTED_CHAR:
    return "UNEXPECTED_CHAR";
    break;
  case PERR_EXPECTED_CLOSE_BRACKET:
    return "EXPECTED_CLOSE_BRACKET";
    break;
  case PERR_EXPECTED_SPEECH_MARK:
    return "EXPECTED_SPEECH_MARK";
    break;
  case PERR_UNEXPECTED_READER_MACRO_SYMBOL:
    return "UNEXPECTED_READER_MACRO_SYMBOL";
    break;
  case PERR_EXPECTED_BOOLEAN:
    return "EXPECTED_BOOLEAN";
    break;
  }
  assert(false && "perr_to_cstr: unreachable");
  return "";
}

typedef struct
{
  lisp_t *result;
  perr_t error;
} pres_t;

perr_t parse(context_t *ctx, input_t *str, lisp_t **ret);
perr_t parse_all(context_t *ctx, input_t *str, vec_t *vec);

int print_perror(FILE *fp, input_t *inp, perr_t error);

#endif